Scaps: Type-Directed API Search for Scala

Type-directed API search, using queries composed of both keywords and type signatures to retrieve definitions from APIs, are popular in the functional programming community. This search technique allows programmers to easily navigate complex and large APIs in order to find the definitions they are interested in. While there exist some effective approaches to address type-directed API search for functional languages, we observed that none of these have been successfully adapted for use with statically-typed, object-oriented languages. The challenge here is incorporating large and unified inheritance hierarchies and the resulting prevalence of subtyping into an API retrieval model. We describe a new approach to API retrieval and provide an implementation thereof for the Scala language. Our evaluation with queries mined from Q&A websites shows that the model retrieves definitions from the Scala standard library with 94% of the relevant results in the top 10.